A variety of disabling diseases affecting the central nervous system have proven responsive to treatment using electrical stimulation of specific anatomic targets within the human brain. Examples of disabling diseases affecting the central nervous system are Parkinson's disease, multiple sclerosis and the like.
At the present time, devices designed to produce deep brain stimulation use a standard set of components including a pulse generator and an electrode. The pulse generator is electrically connected to the electrode and the electrode is surgically implanted within a patient's brain. The pulse generator can produce a modulatable electrical field/current. At the present time, the electrode elements have four electrode contacts arranged as narrowly spaced bands on the terminal end of a stimulating electrode.
The physiologic effect of electrical stimulation can be modulated by altering the amplitude, frequency or pulse width of the electrical current, emitted from the electrode deeply implanted within the patient's brain.
Because the current deep brain stimulating probes have four electrodes, it is currently possible to achieve a certain limited degree of flexibility in the electrical “footprint” generated by the electrode by changing which electrode is operating, and the other parameters discussed above.
If the initial surgical placement of the electrode in the brain is sufficiently “off-target,” it is impossible to capture the target within the available “footprint” of the electrical field generated by the electrodes of the currently available deep brain stimulating devices.